Here's a sentence I didn't expect to write on a shop blog: if you get drug tested for sport, don't buy our broad-spectrum oil.

Bear with me.

A sports scientist at Liverpool John Moores University put thirty-six people on a broad-spectrum CBD supplement for ten weeks. Nothing exotic. The sort of bottle you'd pick up in any health shop. At the end of it he sat them on a bike for ninety minutes and took urine before and after.

Before the ride, cannabigerol showed up in 42% of samples. After it, 74%. Cannabidivarin went from 68% to 84%.

Nobody took anything extra. Same bottle, same dose, same morning. The only variable was ninety minutes of moderate cycling.

Both of those compounds are banned by the World Anti-Doping Agency. CBD isn't. That's the whole problem, in three sentences.

Why exercise would do that

Fat, probably.

Cannabinoids don't dissolve in water the way most of what you swallow does. They're fat-soluble, so they park themselves in fatty tissue and sit there quite happily. Exercise burns fat. Burn the fat, and whatever was stored in it goes back into circulation, through your kidneys, and into a sample pot.

Researchers have been arguing about that mechanism in cannabis studies for years without ever pinning it down properly. What's new here is watching it happen in people taking something legal, non-intoxicating, and bought over the counter.

The full write-up is in Andrew Gillham's 2026 doctoral thesis if you want the methods.

"Broad-spectrum" is doing a lot of quiet work

There are three kinds of CBD on any shelf, and the difference between them is a subtraction problem.

Full-spectrum keeps everything the plant made, THC included, inside the legal UK limits. Isolate strips it all back until only CBD is left. Broad-spectrum sits in the middle: THC removed, everything else kept.

The middle option sells well, and you can see why. THC-free, so no legal headache, but you keep the rest of the plant. It's a sensible product for most people. I stock it. I'd sell you one tomorrow.

THC-free and cannabinoid-free are not the same claim, though. The other cannabinoids are the entire reason broad-spectrum exists as a category. They're what you're paying extra for.

And on WADA's 2026 Prohibited List, CBD is the only cannabinoid that isn't banned. Not the only one with a limit to stay under. The only one allowed through the door at all.

Go and look at one of our own broad-spectrum oils. Ingredients: MCT oil, broad-spectrum isolate, minor cannabinoids, can include CBG and CBC. That's an honest label, printed where anyone can read it. It's just that for one particular customer it's a list of reasons to buy something else, and nobody has ever bothered to tell them.

Before anyone panics

If your drug test happens at work, this almost certainly isn't about you.

UK workplace screening looks for THC metabolites. It doesn't look for CBG. It has no interest whatsoever in CBDV. Anti-doping rules are written vastly wider than employment screening, because they're chasing performance enhancement and recreational use in sport rather than auditing your supplement drawer. A bump in CBG isn't something a standard workplace panel is built to find, and nobody reading one would care if it were.

So the audience for this is narrower than the headline suggests. Athletes tested under UK Anti-Doping or an equivalent body. Some armed forces and police roles. A handful of professional contracts. If that's you, keep reading. If it isn't, you've just learned something odd about body fat and you can get on with your day.

What this doesn't prove

Thirty-six people isn't many.

They were healthy volunteers, not athletes carrying an athlete's training load or an athlete's body composition. It was one product out of the several hundred on sale in this country. Ten weeks of daily use is a real exposure, but it isn't everyone's habit. And one ninety-minute ride is one kind of exercise.

Detection also isn't a threshold breach. WADA's THC limit sits at 150 ng/mL in urine, in-competition only. A threshold breach isn't a sanction either. There's a process, and it involves humans.

First result. Interesting. Not gospel. Anyone presenting it as settled wants something from you.

What to actually do about it

Buy the one with less in it. That's the whole answer, and it's dull.

Our 99% CBD isolate is CBD and not a great deal else. THC-free, supercritical CO2 extraction, GMP certified, ten quid a gram. White powder, no flavour, dissolves into fat or sugar with a bit of gentle heat, so it goes into a coffee or a yoghurt without announcing itself. There's a longer guide to using it if you've never handled powder before, because it is genuinely a bit fiddly.

Three things I'd rather say now than have you find out later.

Ninety-nine per cent pure leaves one per cent that isn't CBD, and the only thing telling you what that one per cent is is a batch-specific certificate of analysis. Ask for one. Ask us for ours.

Isolate isn't certification. If your livelihood rides on a clean test, what you actually want is Informed Sport or BSCG, where screening a batch against the prohibited list is somebody's literal job description. Isolate improves your odds. Certification is the paperwork you can put in front of a panel.

And a gram is a thousand milligrams. The Food Standards Agency has advised 10mg a day since October 2023. You can't judge that by eye, and I'd rather you spent twelve pounds on a milligram scale, or bought a pre-dosed capsule, than guessed.

Nobody lied

That's the bit I keep coming back to. There's no villain in this story. The label said broad-spectrum, and the bottle contained broad-spectrum.

It's that somebody, years ago, picked a phrase because it sounded like abundance. Fuller. Richer. More plant for your money. And underneath the marketing it turns out to be a precise chemical statement that matters enormously to roughly one customer in fifty, who had no reason on earth to know it.

Most words on most packaging are quietly doing a job nobody mentioned. Turning the box over is a cheaper habit than anything I could sell you.

CBD products are not medicines and cannot diagnose, treat or cure disease. If you are subject to anti-doping testing, take prescription medication, or are pregnant or breastfeeding, speak to your doctor, pharmacist or anti-doping officer before using any CBD product. Athletes should confirm their obligations with their own governing body rather than relying on general guidance.

Sources

• Gillham, A. et al. Daily Use of a Broad-Spectrum Cannabidiol Supplement Produces Detectable Concentrations of Cannabinoids in Urine Prohibited by the World Anti-Doping Agency: An Effect Amplified by Exercise. Liverpool John Moores University. Record
• Gillham, A. (2026). The Role of Cannabidiol in Sport: Mechanistic Insights. PhD thesis, Liverpool John Moores University. Full text
• World Anti-Doping Agency, 2026 Prohibited List. Cannabinoid status and the 150 ng/mL urinary THC threshold, in-competition only. WADA · Summary and analysis
• Food Standards Agency and Food Standards Scotland, updated consumer advice on CBD, October 2023. Recommended limit of 10mg per day for healthy adults. FSA
• Food Standards Agency, cannabidiol (CBD) business guidance. FSA
• UK Anti-Doping, athlete guidance on supplements and prohibited substances. UKAD
• Amariti, J. et al. A comparison of advertised versus actual cannabidiol (CBD) content of oils, aqueous tinctures, e-liquids and drinks purchased in the UK. Journal of Cannabis Research. Study